Exodus 24:4-7

4So Moses wrote down all the words of Adonai, then rose up early in the morning, and built an altar below the mountain, along with twelve pillars for the twelve tribes of Israel.

5He then sent out young men of Bnei-Yisrael, who sacrificed burnt offerings and fellowship offerings of oxen to Adonai.

6Then Moses took half of the blood and put it in basins and the other half he poured out against the altar.

7He took the Scroll of the Covenant and read it in the hearing of the people. Again they said, “All that Adonai has spoken, we will do and obey.”